CHEMICAL WEATHERING PROCESSES ON THE VANTAGE PEAK NUNATAK,JUNEAU ICEFIELD,SOUTHERN ALASKA

On the Vantage Peak nunatak in the Juneau Icefield of southeastern Alaska, grus and soils display evidence of extensive chemical alteration in a self-evidently periglacial environment. Accompanying the alteration of bedrock to grus and soil is a decrease in grain size. Grus is dominated by very coarse sand while the soils are predominantly fine sand. Grain-size reduction is attributed primarily to mineral grain dissolution. Total chemical analyses show that alkali earths (calcium and magnesium) and alkalis (sodium and potassium) are lost as weathering progresses, while silicon and iron increase relative to resistant elements. Secondary clay minerals present in the grus and soils appear to have been derived from clay-size primary minerals. Vermiculite is the principal secondary clay mineral and appears to have formed by the alteration of biotite. Scanning electron microscopy shows that quartz and feldspars are primarily weathered by dissolution with no evidence of feldspar transformation to secondary clays. Superimposed on these weathering transformations is evidence of eolian processes. Chemical weathering processes, notably dissolution and clay mineral transformation, do occur in the periglacial environment of the Vantage Peak nunatak and are clearly an important component of the periglacial geomorphic process suite.     

Tropical cyclone-tornado casualties

Landfalling tropical cyclones often produce tornadoes. This study investigates how hazardous these tornadoes are to human life by analyzing the resultant casualties, which includes fatalities and injuries. From 1995 to 2009, 63 tropical cyclones made landfall in the United States producing a reported 1,139 tornadoes. Most tornadoes resulted in no casualties but a few extreme cases indicate that the potential exists for a substantial number of casualties. Temporal and spatial analyses indicate that most casualties occur when and where the physical risk of tornadoes is elevated.     

Application of support vector machine and relevance vector machine to determine evaporative losses in reservoirs

This article employs Support Vector Machine (SVM) and Relevance Vector Machine (RVM) for prediction of Evaporation Losses (E) in reservoirs. SVM that is firmly based on the theory of statistical learning theory, uses regression technique by introducing ε‐insensitive loss function has been adopted. RVM is based on a Bayesian formulation of a linear model with an appropriate prior that results in a sparse representation. The input of SVM and RVM models are mean air temperature (T) ( °C), average wind speed (WS) (m/sec), sunshine hours (SH)(hrs/day), and mean relative humidity (RH) (%). Equations have been also developed for prediction of E. The developed RVM model gives variance of the predicted E. A comparative study has also been presented between SVM, RVM and ANN models. The results indicate that the developed SVM and RVM can be used as a practical tool for prediction of E. Copyright © 2011 John Wiley & Sons, Ltd.     

Faecal microbial contamination of watercress (Nasturtium officinale) gathered by a Maori protocol in New Zealand streams

A study was carried out to determine the food safety status of watercress (Nasturtium officinale) harvested from rural streams under Maori protocol. Sixty‐five sample bunches (c. 500 g) were collected from four streams in the Waikato region of New Zealand each summer from 2005 to 2007. Two streams, Southern Enclosure and Te Waihou, were within reserves and the other two, Mangapiko and Piopio, flowed through pastoral farms. To assess faecal contamination status, Escherichia coli and thermotolerant Campylobacter were measured on watercress as collected and E. coli counts assessed against the New Zealand guideline for ready‐to‐eat foods (satisfactory: <3 E. coli per g). To determine whether washing would ensure the watercress met food safety standards, an additional 6 bunches were collected and washed in running tap water (household regime). A further 15 bunches were washed by a simulated commercial triple washing regime. At harvest, 16 of 17 watercress samples collected from the Southern Enclosure and 11 of 22 from Te Waihou met the satisfactory criterion for ready‐to‐eat food, but only 1 of 17 from Mangapiko and none of 9 from Piopio were satisfactory. No Campylobacter was recovered from any sample of watercress collected from the four sites. After washing in running tap water, E. coli numbers still exceeded the satisfactory criterion. Commercial triple washing was more effective in ensuring satisfactory watercress, but of the 15 samples subjected to this regime, only 6 met the satisfactory criterion. Escherichia coli remained firmly attached to watercress leaves after both washing regimes (presumably in biofilms). Overall, these findings suggest that it is not advisable to use watercress harvested from rural streams as a raw salad vegetable, particularly from those affected by pastoral farming.     

Encapsulation of limestone waste in concrete after arsenic removal from drinking water

Arsenic is one of the many naturally occurring contaminants in drinking water. Although various treatment technologies can remove arsenic, most suffer from a common problem of disposal of arsenic-enriched waste after treatment. This project focused on improving a limestone-based disposal technique by encapsulating the arsenic-enriched limestone waste in concrete. The research work determined the compressive strengths of the concrete cubes prepared using treated limestone after arsenic removal and determined the amount of leaching from the arsenic-encapsulated concrete. The removal of arsenic was done with batch experiments using 0.5–1 mm sized Minnekahta Limestone. The efficiency of the limestone in removing arsenic ranged from 85.9 to 95.5%. The amount of arsenic adsorbed onto the surface of each gram of limestone ranged from 0.8 to 3.9 μg. Compressive strength results of concrete cubes prepared by incorporating arsenic-enriched limestone showed typical strength curves at 1, 3, 7 and 28 days. Leaching of arsenic was less than 0.05 mg/L, which is 1/100 of the US Environmental Protection Agency’s standard for disposal of arsenic in a landfill. Hence, encapsulating the arsenic-enriched limestone in concrete has potential for recycling the waste material, thereby reducing disposal costs of the limestone-based removal method.     

Nutrient availability in support of Karenia brevis blooms on the central West Florida Shelf: What keeps Karenia blooming?

Identifying nutrient sources, primarily nitrogen (N) and phosphorus (P), sufficient to support high biomass blooms of the red tide dinoflagellate, Karenia brevis, has remained problematic. The West Florida Shelf is oligotrophic, yet populations >10⁶ cells L⁻¹ frequently occur and blooms can persist for months. Here we examine the magnitude and variety of sources for N and P that are available to support blooms. Annual average in situ or background concentrations of inorganic N in the region where blooms occur range 0.02–0.2 μM while inorganic P ranges 0.025–0.24 μM. Such concentrations would be sufficient to support the growth of populations up to ∼3×10⁴ cells L⁻¹ with at least a 1 d turnover rate. Organic N concentrations average 1–2 orders of magnitude greater than inorganic N, 8–14 μM while organic P concentrations average 0.2–0.5 μM. Concentrations of organic N are sufficient to support blooms >10⁵ cells L⁻¹ but the extent to which this complex mixture of N species is utilizable is unknown. Other sources of nutrients included in our analysis are aerial deposition, estuarine flux, benthic flux, zooplankton excretion, N₂-fixation, and subsequent release of organic and inorganic N by Trichodesmium spp., and release of N and P from dead and decaying fish killed by the blooms. Inputs based on atmospheric deposition, benthic flux, and N₂-fixation, were minor contributors to the flux required to support growth of populations >2.6×10⁴ cells L⁻¹. N and P from decaying fish could theoretically maintain populations at moderate concentrations but insufficient data on the flux and subsequent mixing rates does not allow us to calculate average values. Zooplankton excretion rates, based on measured zooplankton population estimates and excretion rates could also supply all of the N and P required to support populations of 10⁵ and 10⁶ cells L⁻¹, respectively, but excretion is considered as “regenerated” nutrient input and can only maintain biomass rather than contribute to “new” biomass. The combined estuarine flux from Tampa Bay, Charlotte Harbor, and the Caloosahatchee River can supply a varying, but at times significant level of N and P to meet growth and photosynthesis requirements for populations of approximately 10⁵ cells L⁻¹ or below. Estimates of remineralization of dead fish could supply a significant proportion of bloom maintenance requirements but the rate of supply must still be determined. Overall, a combination of sources is required to maintain populations >10⁶ cells L⁻¹.     

The ordovician (caradoc) volcanic rocks of montgomery,Powys, N. Wales

The Ordovician (Caradoc, Soudleyan) rocks of Montgomery, Powys are shales interbedded with locally conglomeratic volcaniclastic sediments composed of andesitic detritus. New formal lithostratigraphic units are proposed: Montgomery Volcanic Group comprising in ascending order: Castle Hill Shale Formation, Castle Hill Conglomerate Formation and Quarry Sandstone and Shale Formation. The volcaniclastic strata are reinterpreted as deposits of a submarine volcaniclastic fan system sourced by contemporaneous andesitic island volcanism. The observed diagenetic sequence is typical of marine volcanic sandstones and was dominated by hydration reactions related to the degradation of abundant unstable volcanic detritus. Diagenesis has resulted in the virtual destruction of original porosity in the volcaniclastic rocks.     

Forestry and agriculture: options for resource allocation in choosing lands for transmigration development

The Indonesian Transmigration program aims to resettle people from heavily populated areas of Java, Madura and Bali in the less developed Outer Islands. The development of a successful program poses problems for the resource planner in balancing three major variables: the economic activity which forms the basis of individual projects, the choice of sites to suit those economic activities, and the background and skills of the potential migrants. This paper concentrates on questions of resource allocation in choosing sites for transmigration development. It is based on the hypothesis that ample land resources are available and that of the three main ecosystems used—tidal swamp forests, mature upland forests, and alang-alang (Imperata cylindrica) grasslands—the economic opportunity costs of using forested lands can be considerable.The biophysical characteristics of the three resource systems are examined and the options for the development of new agricultural sites or sustained-yield forestry are explored through the use of a Net Present Value Analysis. The analysis suggests that the choice is not one of forestry versus agriculture but that, with proper consideration of site selection and use of inputs and cultural practices, both forestry and agriculture can be developed. The main conclusion is that alang-alang grasslands provide potential sites for sustained agricultural production which avoid the loss of long-term benefits that can be derived from well-managed forests.     

The scattering of regular surface waves by a fixed,half-immersed,circular cylinder

A train of regular surface waves is incident upon a fixed, half-immersed, circular cylinder; the waves are partially reflected and partially transmitted, and also induce hydrodynamic forces on the cylinder. In order to give a theoretical study of this problem, we make the familiar assumptions of classical hydrodynamics and then solve the linear, two-dimensional, diffraction boundary-value problem, using Ursell's multipole method. Accurate numerical results are presented (in the form of tables) for four important (complex) quantities; these are the reflection and transmission coefficients, and two dimensionless coefficients which describe the horizontal and vertical forces on the cylinder. We have also made an experimental study, in which we measured the forces on the cylinder, and the reflection coefficient. These measurements are compared with the linear theory, and also with other experimental data; discrepancies are noted and an attempt to analyse them is made. We have also measured the mean horizontal forces on the cylinder; these results are compared with the predictions of a simple formula obtained by Longuet-Higgins.     

Polarization measurements with an imaging gamma-ray telescope

The proposed Tracking and Imaging Gamma-Ray Experiment (TIGRE), operating in the 0.3–100 MeV energy interval, will be an efficient polarimeter with a modulation factor of 50% at 0.5 MeV. The polarization detection parameters of TIGRE were estimated using a Monte Carlo simulation modified to include the polarization dependence of the Klein-Nishina formula. Using Compton scattering of low energy photons and approximately 3 acceptance angle after scattering, TIGRE will be able to measure strong sources with 20% fractional polarization at 3 significance in a typical balloon-borne exposure and 5% during a 4-week satellite observation.